Curved Steel?

So, I am looking around in the "boneyard" (where all the various parts are waiting) and I see these curved steel beams. It's a just slight curve, a few degrees.
These are some of our roof beams!
One of the fantastic features of this building design is the roof. We challenged the architects to design a 50 year roof. It was determined that the most durable, most efficient, most leak proof, most aerodynamic, and most continuous roof would be a curved roof!
This type roof is called a "radial roof" and is a gentle sloping curve. (Recently, Grandfather Mountain went with a radial roof design on their new building.) Soon, the steel erectors will be setting these roof beams in place.
I find myself wondering what the radius of this curve is? It is not anywhere near as great as a dome, more like a shallow bowl. I bet there is a math student who could find an answer, maybe a teacher will develop a problem. I see there are 90 degree and 45 degree angles what is the missing component that would help us figure out the degree of curve?

Most of the roof will be three pieces in width, some will be four wide. This continuous roof will have to cover the width of the gym and commons area. It will eventually be a gray metal roof.